Spark-plug.



F. E. HARPST.

SPARK PLUG.

APPLICATION FILED 00T-. 27,1910.

Patnted June 27,1911.

Snow whoa [1%505Zf has special reference to a spark tion consists ingeneral I --m the accompanying drawings,

- mg a contracted enable the plug to FEED E. HARPST, OF HOUSTQN, TEXAS.

SPARK-PLUG.

Specification of Letters Patent.

Application filed October 27, 1910. Serial No. 589,399.

To all whom it may concern:

Be it known that I, FRED E. HARPST, a citizen of the United States,residing at Houston, in the county of Harris, State of Texas, haveinvented certain new and useful Improvements in Spark-Plugs; and I dohereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in .the art towhich it appertains to make and 7 use the same.

relates to spark plu s and plug or use with internal combustion motorknown fact; that much trouble This invention It is a well is experiencedthrough the cracking of the porcelain insulator commonly used in sparkplugs, this cracking being brought about by the intense heat conditionsof the plug when t e engine is running. L y The principal object of thepresent invention is .to provide a device of this character wherein theporcelain will at all times be kept cool. Thesecond object of theinvention is to provide means for keeping the terminals clean this beingaccomplished bycausing a current of. air or gas from carbureter to passthrough check valve then aroundinsuatorand down through spark ap.

With the above'andother objects in view, aswill be hereinafter apparentthe invenof certainnovel dc; tails of construction and combinations ofparts hereinafter fully described, illustrated and specifically setforth in the claims. t r

In the accompanying drawings, like'char-f acters of reference indicatelike parts in the several views, and Figure 1 is a vertical sec-- tionof'a spark plug constructed in accord- .ance with this invention, 2 is asection on theline 2-2 of Fig.1. i The spark plug comprises a shell 10which isthreadedat oneend as at 11 to permitits being,screwed intothecombustion chamber of, the engine. Theother end of theplug isprovided with the usual polygonal nut 12 to be grasped with a wrench.The plug has a bore extending from one end tothe'othe'r end, and thisbore consistsof .a lower or inner portion 13 havortion 14 immediatelthereabove. Ju'st above the contracted portion the bore is again widenedout, as shown; at 15, and terminates at its upper end a plug by means ofa 'carbureter at such that the mixture -two being so arrantg tion 19fits the reduced portion 14 of the bore and extends within the portion13 of both but terminates at a point greatly removed from the threadedend of the shell. Between the end threaded end 11 is surrounded byradiator fins 20. Surrounding the upper end of the portion 13 of thebore is an annular chamber 21 which communicates with. small openings orperforations 22. Projecting from one side of the shell is a lug 23 whichis hollow and threaded internally. The hollow of this lug communicateswith the annular chamber 21 by means of a passage 24. Within this hollowscrewed a valve cage 25 containing a ball valve 26 and spring 27 soarranged as to permit the passage of air and gas inward but to preventthe exploded charge frompassing 0utward.- The valve cage is held at theinner end of the hollow, and the remaining threads are utilized toconnect the spark pipe not deemed necessary tobe shown to the intakemanifold or a point as to, be below the throttle in same. Through theside wall of this portion 23 there is provided a small p n hole 27' forthe purpose of admitting air during the suction stroke of the engine soball valve will have an excess of air. 7

' Extending through the insulator 1s a long terin'inal 28 which isarrang side wall of thebore is a term1nal 29 the ed that a gap is formedhe terminal 28 andthe etween the side 0 end of the terminal vided withthe usual with-the ordinary thum nut -32 between which and the nut 31the'end'o'f the con"- ductor wire is clamped. v r v 'QIt is to beparticularly noted that the location of the a r "such that-with eachsuction strokefoftthe' 1 v of carbureted air in'whichan excess of air'isdrawn in andthat" this chargepassing in through the ball valve inner endof the; insulator is englnef'a c harge here 1s 29.- The plugis pro-jpacking or backin nut "30 and terminal adjustin .nut' 31 aswe as'Patented June 2'7, 1911.- I

of the insulator 19 and the of the spark plug the shell the bore byseries of portion is which passes throughi'the .95 ed axiallypf the boreand extending radlally from the loo follows around the annular chamberand passes through the opening 22 so that the entire inner end of theinsulator is surrounded by'a sheath of cool air or gas. It is-further tobe observed that this incoming air or gas is kept cool by reason of thefact that the heat from the inner end of the spark plug is radiated awayfrom the upper end by means of the fins 20. This incoming chargesweeping through the gap of the-terminals effectually blows off anydeposit of carbon or soot and keeps the. terminals in proper conditionsfor sparking at all times. Finally the remote position of the end of theinsulator from the inner end of the spark plug prevents the flame of theexplosion from backing up intothe bore 13 and depositing soot on thecold porcelain with the consequence that the passage surrounding thesame becomes choked.

There has thus been provided a simple and efficient device of the kinddescribed and for the purpose specified.

What is claimed is -1. In a sparking plug, a shell provided with a'boreextending therethrough and having an annular chamber at one end spacedfrom and surrounding said bore, .an insulator extending into said boreand having its inner end in spaced relation to. the bore and termmatmgad acent said chamber whereby air entering the chamber will impinge uponthe insulator,..a projection on one side of said shell opposite saidannular chamber, said projection having a hollow body communicatingwithsaid chamber, a check valve held in said projection, and

- sparking terminals supported by said insulator and the inner endof theshell.

2. In a spark plug, a shell rovided with a bore extending therethroughand having an annular chamber at one end spaced from and surroundingsaid bore, said shell being provided with a series of openings betweenthe chamber and the bore, an insulator extending into said bore andhaving its inner end in spaced relation to the bore and terminatingadjacent said'openings whereby air entering the openings will impingeupon the insulator, said shell opposite said annular chamber, saidprojection having a hollow body communicating with said chamber, a checkvalve a projection on one side ofheld in said projection, saidprojection being threaded for connection to a pipe and having a radialopening communicating from the exterior to the hollow portion, and

sparking terminals carried by said insulator and the inner end of saidshell.

3. In a spark plug, a shell provided with a bore extending therethroughand having an annular chamber at one end spaced from and surroundingsaid bore, said shell being provided with a series of openings betweenthe chamber and the bore, an insulator extending into said bore andhaving its inner end in spaced relation to the bore and terminatingadjacent s'aidiopenings whereby air entering the openings will impingeupon the-insulator, a projection, on one side of the shell opposite saidannular chamber, said projection having ahollow body communicating withsaid chamber, a check valve I held in said projection, said projectionbeing threaded for connection to a pipe and having a radial openingcommunicating from' the exterior to the hollow ortion, sparkingterminals carried by said insulator and the in'ner end of said shell,and radiator fins surrounding said shell between the insulator and theinner end of the shell.

In testimony whereof, I aflix my signature, in presence of twoWitnesses.

FRED E. HARPST.

Witnesses: I WJD. STEPHENS,

, R. V. SoLoMoN.

